


You're Kidding

by LunarFlare64



Category: Undertale (Video Game)
Genre: Alphys and Undyne aren't married yet, Alphys is pissed, Background slowburn Mettaton/Papyrus, Bad Puns, Chronic Fatigue, Domestic Fluff, Established Alphys/Undyne (Undertale), Established Sans/Toriel (Undertale), Eventual marriage (for more than one couple), F/F, F/M, Family Fluff, Flowerpot Flowey, Ghost Chara (Undertale), How monster reproduction works is up to you, M/M, Mettaton and Papyrus are gay disasters, Mettaton better watch his ass because Alphys WILL catch that bouquet, Post-Undertale Pacifist Route - "I want to stay with you.", Pregnancy, Recovery, Sans and Toriel are excited parents, Sans has chronic fatigue syndrome, Swing Dancing, Takes place around three years after canon, Those moustache glasses disguise thingies (and a lot of them), Toriel and Asgore are slowly patching things up, Unplanned Pregnancy, Wedding Planning, Wedding pranks (from the bride and groom, not to them), pure fluff, supportive asgore, unconventional weddings
Language: English
Status: In-Progress
Published: 2021-02-22
Updated: 2021-02-22
Packaged: 2021-03-12 08:07:15
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,019
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29631612
Author URL: https://archiveofourown.org/users/LunarFlare64/pseuds/LunarFlare64
Summary: Sans had never really put much thought into having kids of his own, what with him first raising Papyrus, then Frisk, Chara, and Flowey when he and Tori became official.But maybe he should have.
Relationships: Alphys/Undyne (Undertale), Asgore Dreemurr & Sans, Asgore Dreemurr & Toriel, Chara & Flowey & Frisk (Undertale), Mettaton/Papyrus (Undertale), Papyrus & Sans (Undertale), Sans/Toriel (Undertale)
Kudos: 14





	You're Kidding

**Author's Note:**

> Get it? Because "kidding" is what it's called when a goat goes into labour? And kids are baby goats? Imagine the pun potential!
> 
> Anyway, don't expect this to update quickly, I'm writing the chapters out of order so who knows when I'll get to chapter 2.

Sans had never thought about having kids...okay, no, he has, he just never thought...that it’d actually happen. At least, not with kids of his own. First he raised Papyrus, then later Frisk, Chara, and Flowey came into the picture after he and Tori became official, and he figured that’d be it, no genetic offspring from him.

Apparently he was wrong.

He stared at the faint little lights humming in his partner’s abdomen, the early stages of a soul forming clear to him while she slept, oblivious to what was going on, what had been happening right under their noses for what had to be weeks now.

Sans ran a hand over his skull, not taking his eyes off the scattered little sparks.

“Fuck.”

* * *

  
Toriel seemed perfectly normal that morning, humming as she flipped blueberry pancakes and poured tea and coffee for her and Sans respectively. Normally the skeleton would watch on with a sleepy kind of contentment, but today he was wide awake, searching for the signs that had to have been there from the start.

“Dear? Are you alright?” Toriel frowned, he must have zoned out, because now she was sitting at the table with him, three plates of pancakes set out in front of them, “did you have another nightmare?”

Sans blinked, shaking himself out of...whatever that was, and awkwardly scratching his skull, “y-yeah, i'm good, no nightmares i mean, just...thinking.”

“What about?” She asked as Frisk hurried downstairs with Flowey in their arms and Chara absently floating behind them.

The skeleton's eyes darted to the trio, then back to the Boss Monster, “you didn’t make any thin pancakes this time, right? you know they crepe me out.”

Flowey groaned as Toriel, Frisk, and Chara laughed. None of the kids noticed Toriel sending Sans a knowing look and a nod, indicating they’d be talking once the kids were out.

“Where’s Papyrus?” Chara asked, glancing out into the hall, “did he leave already?”

Toriel nodded, “he and Mettaton planned to hang out today, and you know how punctual he likes to be when it comes to him.”

“right" Sans snickered, “wouldn’t want to be late for ’hanging out'.”

Toriel giggled too, and the soulless and formless children both rolled their eyes. As always, Frisk was excited to hear about Papyrus’ growing relationship with the robot, and began signing a variety of questions.

“c'mon kid, you know we don’t know the answer to any of that, and even if we did we wouldn’t tell" Sans chuckled, closing an eye socket, “believe it or not, even Pap likes his privacy sometimes.”

Frisk pouted, but Sans simply shook his head and gestured to the pancakes that were starting to get cold.

They finished their breakfast and helped the kids get ready, Asgore was taking the three of them out to a theme park for the day with Alphys and Undyne, leaving Sans and Toriel to have the house to themselves for once (Undyne had pointed that out with a suggestive wiggle of her brows, but honestly they were just gonna spend the day on the couch laughing at shitty movies).

Sans had been looking forward to their lazy day, but of course his bad luck had to come in and hand him a serious topic for them to focus on instead. Yeah it was good news, once the shock wore off he knew he’d be just as excited as his partner was guaranteed to be, but having a kid was some serious stuff.

They waved goodbye as the kids joined Alphys and Undyne in Asgore’s overly large car, then turned back into the house and happily dropped onto the couch together.

Toriel didn’t say anything at first, which Sans was grateful for, he wanted to enjoy the house's rare moment of silence while he could.

They laid there, comfortably curled up together for what felt like hours, before Sans heard Toriel sigh, and he knew it was time to talk.

“So, what's been bothering you, dear?” Toriel hummed, absently tracing lines over his skull.

Sans had been trying to think of how to break the news to her all morning, and honestly he still had no idea what to say, so he just let the words tumble out, knowing she could piece his scrambled thoughts together, “do you- have you been feeling...different lately?”

“Different? In what way?”

“Like, have you felt anything unusual, maybe...familiar? From a long time ago?” Sans cringed, not sure if he was even asking the right questions, its not like he's been pregnant, does pregnancy even feel different? Sure there are symptoms, but he was fairly certain she hadn’t dealt with any of the obvious ones yet, without that would she even notice?

Toriel hummed, looking up in thought, “I don’t know about familiar, but I’ve been feeling rather cheerful these past few weeks, but slightly drained at the same time, I feel like getting up to run and play with the kids, but don’t quite have the energy for it. I figured it was just my true age beginning to show, do you think its something else?”

Sans cringed, “that sounds about right...”

“What is it, honey?” Toriel frowned, worry beginning to show.

He sat up, turning around to face her and holding out a hand, “check my magic.”

Toriel blinked, confused but obliging nonetheless.

He could feel her magic reaching out through their interlaced fingers, but before she could look deeper he directed her hand down to her abdomen, and her magic left him in favour of the familiar yet unfamiliar source of magic inside her.

He waited, watching as her confused expression fell in favour of shock and disbelief.

He waited still.

He saw the tears forming in her eyes as realisation sunk in.

She moved her free hand to join the other at her abdomen, seeming lost in the sensation of the young magic inside her.

She looked to him as if needing confirmation, as if he would know better, which Sans doubted, but he nodded to her anyway, “i- i saw them this morning, while you were asleep.”

The tears increased, and Sans felt his own come in response as she spoke, “I'm...”

“yeah" Sans chuckled.

A choked sob left the Boss Monster, and she allowed herself to fall into his arms as the dam broke, never taking her hands off her abdomen.

* * *

  
The news had managed to sink in a little more for the skeleton while he held her, listening to the sound of her overjoyed sobs combined with hints of the pain that had never left her since her eldest's death, even after he returned as Flowey.

She managed to settle down after a few minutes, and was now leaning back into the couch, looking into space in dazed wonder.

Sans was in a similar state.

“we’re having a baby" Sans whispered, as if breaking the silence would take it all back.

Toriel nodded.

Neither of them spoke again for quite some time, content to let this new reality sink in in silence.

Until Toriel shot up with a gasp, “I’m over three hundred years old...”

Sans blinked, “uh...yeah?”

“Sans" Toriel turned to him, a mixture of delight and worry in her expression, “we Boss Monsters...the number of children we can have in a pregnancy increases as we age, at my age I'm more likely to have twins, maybe even more, than a single child.”

The skeleton froze, not even the lights in his eyes moving, “i've...uh...never heard about that one...”

Toriel shook her head, “normally my kind has children early on and we start aging before we can reach that point, and with Asgore and I being the last full-soul Boss Monsters that knowledge wouldn’t be common.”

“so...it’ll probably be twins?” Sans asked.

Toriel nodded.

“huh" Sans finally blinked, though his expression didn’t change.

“...Sans?” 

She looked so nervous, he hated leaving her hanging like this, but he couldn’t bring himself to move as this new information sunk in. Twins...wow, uh...okay...the house will definitely be crowded, with five kids, him and Tori, and Papyrus. Loud too. 

Papyrus and the kids will want to pitch in, along with all their friends, that’s just how their big weird family was, so despite what his anxiety was quick to tell him, he and Toriel wouldn’t be left alone to deal with it all.

So...twin Boss Monster skeletons. 

He tried to think of what their family would look like with the new additions. He and Toriel smothering the twins with love, Papyrus being the world’s best uncle, Frisk doing their best to be a responsible big sibling while Chara and Flowey try to teach the little ones curses. 

Then there was their extended family, Alphys and Undyne would be obsessed with the kids, and it wasn’t hard to picture the twins loving the eccentric pair. Asgore had always been surprisingly supportive of his and Toriel's relationship, and would be overjoyed to meet the twins, and the little hybrids would probably be as delighted by his big doofy nature as all the other monster children that met the king.

Mettaton...well, it kinda depends on how far his and Papyrus’ relationship had gotten by then, he’d be their overly sparly extravagant uncle either way, but if he and Papyrus were together...their combined energy and love for the little ones would result in some intense spoiling.

By this point Sans’ eyelights had taken on a star shape, he’d forgotten all about reassuring Toriel, but the former queen had noticed the stars, allowing her to relax.

“Are you okay there, dear?” Toriel giggled at the sight of his dreamy expression.

“huh?” Sans blinked, coming back to earth at the sound of her voice, though his dopey grin remained, “oh, yeah, its just- yeah, twins would be great.”

Toriel smiled, gathering the skeleton in her arms and humming happily, “this is really happening.”

Sans nodded, combing his fingers through her fur, before trailing a hand down to her abdomen to feel the forming souls, “when will their souls be complete? Do you know?”

The Boss Monster rested a hand next to Sans', concentrating for a moment, “not long, maybe another week or two? They feel surprisingly whole despite how scattered they are.”

When Sans had seen the souls that morning it looked like they were much younger than that, but maybe that was because he thought there’d only be one, not to mention he’d never seen the early stages of soul formation in person before.

“can’t wait" Sans grinned.

They sat there feeling the little souls, grins growing wider with each little pulse of magic.

And then Sans came to a realisation that made his eyelights sparkle.

“hey, Tori" Sans snicked, “you know this means we’re gonna need some more womb.”

Toriel blinked, confused for a moment, before a gasp of delight left her, “you’re right! Baby we could get some renovations done?”

Sans snorted, “we’ll have to start soon if we want the place ready before the kids are bone.”

They continued on like that for a while, making vague renovation plans laced with enough puns to make Papyrus cry.

Speaking of Papyrus and the rest of their family, Toriel remembered they’d all be home in just a few short hours.

“We need to decide if we’re going to wait to tell them" Toriel frowned.

Sans shrugged, perfectly fine with letting his partner decide, “do you wanna wait?”

Toriel hesitated, “well...I’m not fond of the idea, I’d love to share the news right away, but...I’d also like to tell each of them separately...”

That’s easy enough to fix, Sans figured, “so we tell them separately tonight, pull them away for, like, an interview, tell them to keep quiet until everyone’s in on it.”

“Sans, an interview involves us asking them questions, not sharing news" Toriel giggled.

“right? its the perfect cover-up” Sans beamed, rather proud of himself.

“Alright, alright" Toriel laughed, happy to have her skeleton here with her for all this, despite how sudden it had been.


End file.
